Just bought 04 cobra w/ 15k miles and seem to be having pinging problems. The car came with K&N filter, billetflow 2.76 pulley, x-pipe and some quite mufflers. At or near wide open throttle and 3000rpm and up she pings, otherwise normal driving is fine. Initially thought the svt dealer put 87 octane in the tank, but after burning up half of the tank I added 91 (the max at chevron in CA) and octane boost. The car came from Tennessee and thought it may have had a chip in the back of the computer to run higher octane, but no luck. Just yesterday the service engine light came on, turned out to be a problem with an original spark plug (the insulator came lose), so today I put in the NGK TR6 plugs, but didnt make a difference. Any suggestions?
ping ping = bad bad 2.76 pulley 91 octane and no tune is not recommended , best bet is to get a sct x-cal or prediator to pull out some timing . p.s. stay out of the throttle til then. Good luck
pinging Thanks very much for the info! Predator was in the plans down the road, and new exhaust is sitting in the garage, will bolt it on and get it to the shop!
IF THE ENGINE IS PINGING DO NOT GO INTO BOOST OR YOU ARE RISKING SERIOUS ENGINE DAMAGE!!!!!! You need to get your car to a dyno and have your A/F ratio checked ASAP! Every time you hear that "pinging", you're possibly eating away at the piston lands... keep it up and you'll be replacing the motor real soon. See photo below... If this car is running a 2.76 pulley does it at least have a chip in the ECM? Please tell me this modified Cobra isn't still running the stock programming!!! U.M.
no chip I checked for a chip and there wasnt one. I am assuming the previous owner must have removed the chip or program tuner before they sold it to the dealer (or perhaps the dealer did), since even running octane boost didnt resolve the pinging. Thats a very horrific picture!!!! enough to make me worry what mine look like!!! I have only had the car for a week and a half, and definitely do not have any intentions of running it, except to the dyno shop now. Even the "qualified" svt dealer has very limited knowledge, regarding aftermarket parts. They were aware it had a non-stock pulley and thought it may be a one step down from stock pulley and was safe to run. Should I swap they pulley so I can get it to the dyno shop? Or is it OK to limp it along without using boost? Thanks for all your info!
You should be safe as long as you don't get on it. Lets just hope the car hasn't been beat on a lot from the time the previous owner traded it in up until you getting your hands on it. Did you happen to get any type of warranty with the car by chance? As long as the dyno shop is relatively close you can drive the car there, just drive the car like there's an egg under the accelerator. Get that baby tuned ASAP and report back to us! U.M.
warranty Yes, I did get an extended warranty, so shes good for 5yrs or 60k miles. Just got the SCT XCalibrator 2 Tuner and booked time next week to take her in as is, before I go bolting on any other mods.
Heres what the plugs look like that came out. Not sure if thats a good indication how the motor use to run. Brightened slightly from the flash.
Coloration doesn't look too bad, looks as if the A/F is a little lean. In your case what you need to be looking for is actual damage to the plugs. Detonation will physically beat the **** out of the plug, break porcelain, etc. Get that damn thing tuned man... U.M.
also looks like you have a valve cover leak around the spark plug hole , if that is oil around the plug at the porcelain.
finally tuned! Finally got her tuned today and the pinging is gone for good at WOT. 2.76 BF w/idlers, K&N FIPK, Mac o/r h-pipe, 2 ch/flows catback, with SCT Xcal2 tune. 455/476 on 91 oct. The boost was registering just over 13psi max (lower then I expected), so perhaps the warmer outside temps (85-90) had something to do with it.
Yup! The temperature and even altitude are definitely key factors in how much boost you make with a specific pulley combo. Those numbers aren't too bad considering you're running a non-ported Eaton in this heat and all. Glad to hear you got her tuned, do you have the dyno sheet to share with us? Just curious as what your A/F ratio looks like. U.M.
I only took home the chart with the HP and Torque curves (attached), another graph had all 3, the A/F was a solid 12.5 line up to let off around 6k rpm.
12.5 is borderline in my opinion. If running stock boost a 12.5 A/F is okay, but for a pullied Eaton most folks would rather have it a little more rich just to be on the safe side. On a positive note you never told us these HP/TQ numbers were from a Mustang Dyno! That makes your numbers even more impressive since the Mustang dynometer normally reads 5-10% lower than the industry standard Dynojet. U.M.
Yes, did forget to mention that. I originally bolted on a Bassani x-pipe but it wouldnt seal, so had to resort to the H-pipe for the dyno run. Also have a new BBK throttle body I want to bolt on after I have the intake ported to match the tb. So when I get those 2 situated I will be taking it back. So what kind of A/F # is preferred?
If I were you I'd save my money and not waste it on the BBK TB. You can make over 600+RWHP with the stock TB. It's not going to gain you anything by replacing the stock TB with the BBK unit. If you want to see more HP/TQ send your stock TB/Inlet/Eaton in and have all three ported. This will easily put you over 500RWHP & 500RWTQ. Keep in mind you'll need fuel upgrades (inectors/BAP/MAF) to support this. As for A/F... Something a little below 12.0 would be safer, around 11.5 to 11.8. U.M.
Listen to Meat he is the Man!! You do need to adress the A/F, your shop should be willing to retune it get it right.
Not sure how soon I can get it back to the shop to adjust the A/F ratio down from 12.5. If I add octane boost or a few gallons of race gas (or anything higher then 91 octane) will that help temporarily richen up the A/F mixture, or will the cpu compensate? Or the shop also gave me a second tune in case I have any pinging issues (They basically said it has a few degrees, maybe more, less timing). thanks.
